The invention relates generally to balers of large round bales and, more specifically, to a drum roller which assists in the support and rotation of a large cylindrical bale forming in the baling chamber of a baler.
The baling industry was revolutionized in recent years by the introduction of baling machines that form large cylindrical bales of crop material having a diameter of up to about six feet and a length of up to about five feet. An example of such a baler is taught in U.S. Pat. No. 4,172,354. As is typical in such balers, the '354 patent teaches the use of a plurality of endless belts in a transversely spaced relation across the width of the baler to define a bale forming chamber. Crop material picked up by the baler is directed into a starting chamber where the material initially forms into a full width cylinder of small diameter. As additional crop material is added to the starting bale, the bale grows into the main baling chamber where it is at least partially supported and rotated by a drum roller. The drum roller is driven at a rotational speed such that its outer peripheral surface in contact with the forming bale moves at the same speed as the bale-contacting surface of the plurality of belts.
In known balers, a plurality of raised, engagement members attach to the outer peripheral surface of the drum roller to assist in engaging and aggressively rotating the forming bale. For example, in the '354 patent, a plurality of longitudinal rods are welded to the surface of the drum roller to act as the raised, engagement members. Such drum rollers work well when the baler is acting substantially as designed and the drum roller is coordinated with the belts. In actual practice, however, the speed of the belts may vary substantially due to accumulation of crop materials or other substances on the support rollers about which the belts are trained or the effective diameter of the drum roller will vary with the crop materials. Not infrequently, the belts speed is greater than the effective surface speed of the drum roller so the bale is counter-rotated with respect to the drum roller. This results in stress and additional loads being imposed on the belt and drum roller drive system with concomitant losses of energy efficiency and drive train lifetime.
Known drum rollers also suffer from the disadvantage of trapping and accumulating crop material in the raised, engagement members. Such trap material reduces the aggressive engagement action of the drum roller.